This invention relates to a method for representing in two spatial dimensions a three dimensional surface which comprises a plurality of viewing planes spaced from one another along a viewing direction. Document No. T120,473, previously filed in the U.S. Patent and Trademark Office Document Disclosure Program on Sept. 12, 1983, relates to this invention.
Various methods for representing a workpiece are known which are more or less well suited to assist a user of a numerically controlled machine tool in programming operations. For example, the brochure identified as "ALTR 81-8 10000" of the firm of Yamazaki Machinery Works, Ltd., Japan, describes a control system identified as Mazatrol T-1. In this system the input program is displayed on a picture screen in the form of a set of tool path contours. This approach to workpiece representation can be confusing, for a tool path contour remains in place even if in later processing operations the former workpiece contour is removed by further treatment to the workpiece. Thus, the finished representation includes not only the contours of the finished workpiece, but also a large number of lines which were all tool path contours at one time during the processing operation. This complexity can very rapidly give rise to representation which is difficult to use.
Furthermore, at the Paris Exhibition "EMO 1983," a control system was disclosed which is described in a brochure of the company MAHO, D-8962, Pfronten. In this control system a workpiece that is being processed with a milling tool is shown in three projections. In order to make it possible to perceive what depth a processing operation has reached, another projection must be viewed, which, does not show all of the contours, but is a presentation of exclusively a respective silhouette. The viewer therefore, has no spatially acting impression of the workpiece image, and various processing planes can be determined visually only by inspecting all three projections. Thus, known types of workpiece representation methods are either not entirely satisfactory, or alternatively are too expensive (as for example the three dimensional representations accomplished with the aid of computer aided design).